Ajax里的东西

net.js 代码

var net=new Object();
net.READY_STATE_UNINITIALIZED=0;
net.READY_STATE_LOADING=1;
net.READY_STATE_LOADED=2;
net.READY_STATE_INTERACTIVE=3;
net.READY_STATE_COMPLETE=4;
net.ContentLoader=function(url,onload,onerror){
    this.url=url;
    this.req=null;
    this.onload=onload;
    this.onerror=(onerror) ? onerror : this.defaultError;
    this.loadXMLDoc(url);
}
net.ContentLoader.prototype={
    loadXMLDoc:function(url){
        if (window.XMLHttpRequest){
            this.req=new XMLHttpRequest();
        } else if (window.ActiveXObject){
            this.req=new ActiveXObject("Microsoft.XMLHTTP");
        }
        if (this.req){
            try{
            var loader=this;
            this.req.onreadystatechange=function(){
            loader.onReadyState.call(loader);
            }
                this.req.open('GET',url,true);
                this.req.send(null);
                }catch (err){
                this.onerror.call(this);
            }
        }
    },
    onReadyState:function(){
        var req=this.req;
        var ready=req.readyState;
        if (ready==net.READY_STATE_COMPLETE){
            var httpStatus=req.status;
            if (httpStatus==200 || httpStatus==0){
                this.onload.call(this);
            }else{
                this.onerror.call(this);
            }
        }
    },
    defaultError:function(){
        alert("error fetching data!"
        +"\n\nreadyState:"+this.req.readyState
        +"\nstatus: "+this.req.status
        +"\nheaders: "+this.req.getAllResponseHeaders());
    }
}

test.htm 代码

function test(){
    new net.ContentLoader('mydata.xml',parseMyData);
}

function parseMyData()
{
       //因为我已经传了 parseMyData 这个函数给 net 做回调函数,
       //所以在这里可以直接使用 net.js 的资源
       var script=this.req.responseText;
       eval(script);
       //使用eval可以执行ajax返回的javascript代码
}

<input type="button" name="button" value="Button" onclick="javascript:test();">
<p>
<div id="myData" style="background-color:#c6d9ef"> </div>